Level 3
One avocado cost 4 times as much as one honeydew. Mrs Zhang bought 2 avocados and 4 honeydews for $15. How much would 20 avocados and 16 honeydews cost? Express the answers to 2 decimal places.
Level 3
The total monthly incomes of 24 men is $51000. 58 of them earn the same monthly income each. Each of the remaining men earns 4 times as much monthly. Find the difference between the higher income and the lower income per month.
Level 3
The ratio of blue to purple stamps Eva had was 5 : 2. The cost of each of the blue stamps was $1 and the cost of each of the purple stamps was $2. Eva sold 40% of the blue stamps and the total cost of the unsold stamps was $455. How many blue stamps did she have left?
Level 3
Some pupils took a Math exam. Their average score was 74.7 marks. One of the pupils' scores was wrongly recorded as 68 marks instead of 86 marks. As a result, the average score was calculated as 73.5 marks. How many pupils sat for the exam?